1. Field of the Invention
The invention relates to a printing control method, and more particularly, to a printing control method capable of increasing the rate of printing through skipping color data having no content and a printing system using the same.
2. Description of the Prior Art
Electrophotography printing devices output an image through a way called ElectroPhotoGraphy (EPG). Such technology includes a number of steps: charging, exposure, developing, transfer, and fusing. When such printing devices are printing an image, a charger of the device first charges a photoconductor with negative charges, which is called the charging process. Then the printing device performs the exposure process by converting the data to be outputted into a form of photo instructions through a light emitting diode (LED) or Laser and the photo instructions will be projected on the photoconductor full of negative charges on the surface. Voltage differences exist between the areas of the photoconductor projected with lights and without lights. The area projected with lights, the exposed area, has higher voltage level than the area not being projected with lights, the unexposed area. A latent image, which is a voltage image expressed with voltage difference, may by formed on the photoconductor through the above process.
Once the latent image is formed on the photoconductor, developing will be the next process. Powdered carbons that have same voltage level as the unexposed area are unable to be attached to the unexposed area due to static propelling force but will be attached to the exposed area that has higher voltage level due to static attraction force. When the exposed area are attached with powdered carbons, and this is called the developing, the attached powdered carbons will be transferred to the paper or any medium, which is called the transfer process. For a multi-pass transfer process, four pass for example, a single charger is commonly used to perform the charging process and it will take the photoconductor to rotate for four rounds when using such charger to process a color page output.
Finally, a hot roller and a pressure roller are used to fix the powdered carbons firmly on the paper or any available medium, which is so called the fusing process.
As described, for an electrophotography printing device to go through four pass transfer and output a color page, the color data mainly includes four color components: cyan, magenta, yellow, and black. It requires the photoconductor to rotate for four rounds before all the four color components are completely transferred to the paper and a color page is finished. Statistically, however, not every page in every printing job contains content of all four color components. It is much more common that text content with simply black component involved is the case, especially for an office like environment. Two-tone printing is also quite usual and full color printing that uses all the four color components also exists, only in a comparably much fewer instances than the black and white printing or two-tone printing. For the black and white printing and two-tone printing, the printing driver program of a computer will routinely convert all the RGB data shown on the display into four color components: CMYK. These four CMYK color components together with their printing control codes will be all sent to the printer. In such way, the printer always goes through a printing job with four colors rounds, the photoconductor rotating four rounds, whatever the data for printing is. Printers using a conventional way like this have problems in promoting the transmission of data and the printing rate of the machine.